The idea is pretty simple. When you log into Google, your friends on Twitter/Blogger/Flickr/LinkedIn, etc who have promoted sites in their social circle will appear prominently in your related search results.

Of course Google has put together an easy video to demonstrate how this works:

Google had previously placed social search items at the bottom of search results.

Additionally, Google has made it easier to privately connect to social networks, instead of displaying your social ties on your public profile.

We’ve given you more control over how you connect accounts, and made connecting accounts more convenient. You can still connect accounts publicly on your Google profile, but now we’ve added a new option to connect accounts privately in your Google Account. (After all, you may not want everyone to know you’re @spongebobsuperfan on Twitter.)

Though this may initially seem mundane, it is actually a great start in countering any long term advantages the Facebook/Bing alliance my have over Google. By signing up just about everybody else in the social world, Google has shown it is capable of harnessing the social graph.